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                                <div class="api-method"><div class="api-method-definition"><h1 id="schedulework">scheduleWork</h1><p>&#x8FD9;&#x91CC;&#x5148;<code>scheduleWorkToRoot</code>&#xFF0C;&#x8FD9;&#x4E00;&#x6B65;&#x975E;&#x5E38;&#x91CD;&#x8981;&#xFF0C;&#x4ED6;&#x4E3B;&#x8981;&#x505A;&#x4E86;&#x4E00;&#x4E0B;&#x51E0;&#x4E2A;&#x4EFB;&#x52A1;</p><ul><li>&#x627E;&#x5230;&#x5F53;&#x524D;<code>Fiber</code>&#x7684; root
</li>
<li>&#x7ED9;&#x66F4;&#x65B0;&#x8282;&#x70B9;&#x7684;&#x7236;&#x8282;&#x70B9;&#x94FE;&#x4E0A;&#x7684;&#x6BCF;&#x4E2A;&#x8282;&#x70B9;&#x7684;<code>expirationTime</code>&#x8BBE;&#x7F6E;&#x4E3A;&#x8FD9;&#x4E2A;<code>update</code>&#x7684;<code>expirationTime</code>&#xFF0C;&#x9664;&#x975E;&#x4ED6;&#x672C;&#x8EAB;&#x65F6;&#x95F4;&#x8981;&#x5C0F;&#x4E8E;<code>expirationTime</code>
</li>
<li>&#x7ED9;&#x66F4;&#x65B0;&#x8282;&#x70B9;&#x7684;&#x7236;&#x8282;&#x70B9;&#x94FE;&#x4E0A;&#x7684;&#x6BCF;&#x4E2A;&#x8282;&#x70B9;&#x7684;<code>childExpirationTime</code>&#x8BBE;&#x7F6E;&#x4E3A;&#x8FD9;&#x4E2A;<code>update</code>&#x7684;<code>expirationTime</code>&#xFF0C;&#x9664;&#x975E;&#x4ED6;&#x672C;&#x8EAB;&#x65F6;&#x95F4;&#x8981;&#x5C0F;&#x4E8E;<code>expirationTime</code>
</li></ul>
<p>&#x6700;&#x7EC8;&#x8FD4;&#x56DE; root &#x8282;&#x70B9;&#x7684;<code>Fiber</code>&#x5BF9;&#x8C61;</p><p>&#x7136;&#x540E;&#x8FDB;&#x5165;&#x4E00;&#x4E2A;&#x5224;&#x65AD;&#xFF1A;</p><pre><code class="lang-js"><span class="hljs-keyword">if</span> (
  !isWorking &amp;&amp;
  nextRenderExpirationTime !== NoWork &amp;&amp;
  expirationTime &lt; nextRenderExpirationTime
)</code></pre>
<p>&#x6211;&#x4EEC;&#x6765;&#x89E3;&#x91CA;&#x4E00;&#x4E0B;&#x8FD9;&#x51E0;&#x4E2A;&#x53D8;&#x91CF;&#x7684;&#x610F;&#x601D;</p><ol><li><code>isWorking</code>&#x4EE3;&#x8868;&#x662F;&#x5426;&#x6B63;&#x5728;&#x5DE5;&#x4F5C;&#xFF0C;&#x5728;&#x5F00;&#x59CB;<code>renderRoot</code>&#x548C;<code>commitRoot</code>&#x7684;&#x65F6;&#x5019;&#x4F1A;&#x8BBE;&#x7F6E;&#x4E3A; true&#xFF0C;&#x4E5F;&#x5C31;&#x662F;&#x5728;<code>render</code>&#x548C;<code>commit</code>&#x4E24;&#x4E2A;&#x9636;&#x6BB5;&#x90FD;&#x4F1A;&#x4E3A;<code>true</code>
</li>
<li><code>nextRenderExpirationTime</code>&#x5728;&#x662F;&#x65B0;&#x7684;<code>renderRoot</code>&#x7684;&#x65F6;&#x5019;&#x4F1A;&#x88AB;&#x8BBE;&#x7F6E;&#x4E3A;&#x5F53;&#x524D;&#x4EFB;&#x52A1;&#x7684;<code>expirationTime</code>&#xFF0C;&#x800C;&#x4E14;&#x4E00;&#x65E6;&#x4ED6;&#x88AB;&#xFF0C;&#x53EA;&#x6709;&#x5F53;&#x4E0B;&#x6B21;&#x4EFB;&#x52A1;&#x662F;<code>NoWork</code>&#x7684;&#x65F6;&#x5019;&#x4ED6;&#x624D;&#x4F1A;&#x88AB;&#x518D;&#x6B21;&#x8BBE;&#x7F6E;&#x4E3A;<code>NoWork</code>&#xFF0C;&#x5F53;&#x7136;&#x6700;&#x5F00;&#x59CB;&#x4E5F;&#x662F;<code>NoWork</code>
</li></ol>
<p>&#x90A3;&#x4E48;&#x8FD9;&#x4E2A;&#x6761;&#x4EF6;&#x5C31;&#x5F88;&#x660E;&#x663E;&#x4E86;&#xFF1A;<strong>&#x76EE;&#x524D;&#x6CA1;&#x6709;&#x4EFB;&#x4F55;&#x4EFB;&#x52A1;&#x5728;&#x6267;&#x884C;&#xFF0C;&#x5E76;&#x4E14;&#x4E4B;&#x524D;&#x6709;&#x6267;&#x884C;&#x8FC7;&#x4EFB;&#x52A1;&#xFF0C;&#x540C;&#x65F6;&#x5F53;&#x524D;&#x7684;&#x4EFB;&#x52A1;&#x6BD4;&#x4E4B;&#x524D;&#x6267;&#x884C;&#x7684;&#x4EFB;&#x52A1;&#x8FC7;&#x671F;&#x65F6;&#x95F4;&#x8981;&#x65E9;&#xFF08;&#x4E5F;&#x5C31;&#x662F;&#x4F18;&#x5148;&#x7EA7;&#x8981;&#x9AD8;&#xFF09;</strong></p><p>&#x90A3;&#x4E48;&#x8FD9;&#x79CD;&#x60C5;&#x51B5;&#x4F1A;&#x51FA;&#x73B0;&#x5728;&#x4EC0;&#x4E48;&#x65F6;&#x5019;&#x5462;&#xFF1F;&#x7B54;&#x6848;&#x5C31;&#x662F;&#xFF1A;<strong>&#x4E0A;&#x4E00;&#x4E2A;&#x4EFB;&#x52A1;&#x662F;&#x5F02;&#x6B65;&#x4EFB;&#x52A1;&#xFF08;&#x4F18;&#x5148;&#x7EA7;&#x5F88;&#x4F4E;&#xFF0C;&#x8D85;&#x65F6;&#x65F6;&#x95F4;&#x662F; 502ms&#xFF09;&#xFF0C;&#x5E76;&#x4E14;&#x5728;&#x4E0A;&#x4E00;&#x4E2A;&#x65F6;&#x95F4;&#x7247;&#xFF08;&#x521D;&#x59CB;&#x662F; 33ms&#xFF09;&#x4EFB;&#x52A1;&#x6CA1;&#x6709;&#x6267;&#x884C;&#x5B8C;&#xFF0C;&#x800C;&#x4E14;&#x7B49;&#x5F85;&#x4E0B;&#x4E00;&#x6B21;<code>requestIdleCallback</code>&#x7684;&#x65F6;&#x5019;&#x65B0;&#x7684;&#x4EFB;&#x52A1;&#x8FDB;&#x6765;&#x4E86;&#xFF0C;&#x5E76;&#x4E14;&#x8D85;&#x65F6;&#x65F6;&#x95F4;&#x5F88;&#x77ED;&#xFF08;52ms &#x6216;&#x8005; 22ms &#x751A;&#x81F3;&#x662F; Sync&#xFF09;&#xFF0C;&#x90A3;&#x4E48;&#x4F18;&#x5148;&#x7EA7;&#x5C31;&#x53D8;&#x6210;&#x4E86;&#x5148;&#x6267;&#x884C;&#x5F53;&#x524D;&#x4EFB;&#x52A1;&#xFF0C;&#x4E5F;&#x5C31;&#x610F;&#x5473;&#x7740;&#x4E0A;&#x4E00;&#x4E2A;&#x4EFB;&#x52A1;&#x88AB;&#x6253;&#x65AD;&#x4E86;&#xFF08;interrupted&#xFF09;</strong></p><p>&#x88AB;&#x6253;&#x65AD;&#x7684;&#x4EFB;&#x52A1;&#x4F1A;&#x4ECE;&#x5F53;&#x524D;&#x8282;&#x70B9;&#x5F00;&#x59CB;&#x5F80;&#x4E0A;&#x63A8;&#x51FA;<code>context</code>&#xFF0C;&#x56E0;&#x4E3A;&#x5728; React &#x53EA;&#x6709;&#x4E00;&#x4E2A;<code>stack</code>&#xFF0C;&#x800C;&#x4E0B;&#x4E00;&#x4E2A;&#x4EFB;&#x52A1;&#x4F1A;&#x4ECE;&#x5934;&#x5F00;&#x59CB;&#x7684;&#xFF0C;&#x6240;&#x4EE5;&#x5728;&#x5F00;&#x59CB;&#x4E4B;&#x524D;&#x9700;&#x8981;&#x6E05;&#x7A7A;&#x4E4B;&#x524D;&#x4EFB;&#x52A1;&#x7684;&#x7684;<code>stack</code>&#x3002;</p><p><a href="context.md"><code>context</code>&#x8BF7;&#x770B;&#x8FD9;&#x91CC;</a></p><p><a href="unwindWork.md"><code>unwindWork</code>&#x8BF7;&#x770B;&#x8FD9;&#x91CC;</a></p><p>&#x7136;&#x540E;&#x91CD;&#x7F6E;&#x6240;&#x6709;&#x7684;&#x516C;&#x5171;&#x53D8;&#x91CF;&#xFF1A;</p><pre><code class="lang-js">nextRoot = <span class="hljs-literal">null</span>
nextRenderExpirationTime = NoWork
nextLatestAbsoluteTimeoutMs = <span class="hljs-number">-1</span>
nextRenderDidError = <span class="hljs-literal">false</span>
nextUnitOfWork = <span class="hljs-literal">null</span></code></pre>
<h5 id="markpendingprioritylevel">markPendingPriorityLevel</h5><p>&#x8FD9;&#x4E2A;&#x65B9;&#x6CD5;&#x4F1A;&#x8BB0;&#x5F55;&#x5F53;&#x524D;&#x7684;<code>expirationTime</code>&#x5230;<code>pendingTime</code>&#xFF0C;&#x8BA9;<code>expirationTime</code>&#x5904;&#x4E8E;<code>earliestPendingTime</code>&#x548C;<code>latestPendingTime</code>&#x4E4B;&#x95F4;</p><p>&#x5E76;&#x4E14;&#x4F1A;&#x8BBE;&#x7F6E;<code>root.nextExpirationTimeToWorkOn</code>&#x548C;<code>root.expirationTime = expirationTime</code>&#x5206;&#x522B;&#x662F;&#xFF1A;</p><ul><li>&#x6700;&#x65E9;&#x7684;<code>pendingTime</code>&#x6216;&#x8005;<code>pingedTime</code>&#xFF0C;&#x5982;&#x679C;&#x90FD;&#x6CA1;&#x6709;&#x5219;&#x662F;<code>lastestSuspendTime</code>
</li>
<li><code>suspendedTime</code>&#x548C;<code>nextExpirationTimeToWorkOn</code>&#x4E2D;&#x8F83;&#x65E9;&#x7684;&#x4E00;&#x4E2A;
</li></ul>
<h5 id="&#x8C03;&#x7528;-requestwork">&#x8C03;&#x7528; requestWork</h5><pre><code class="lang-js"><span class="hljs-keyword">if</span> (
  !isWorking ||
  isCommitting ||
  nextRoot !== root
)</code></pre>
<p>&#x8FD9;&#x4E2A;&#x5224;&#x65AD;&#x6761;&#x4EF6;&#x5C31;&#x6BD4;&#x8F83;&#x7B80;&#x5355;&#x4E86;&#xFF0C;<code>!isWorking || isCommitting</code>&#x7B80;&#x5355;&#x6765;&#x8BF4;&#x5C31;&#x662F;&#x8981;&#x4E48;&#x5904;&#x4E8E;&#x6CA1;&#x6709; work &#x7684;&#x72B6;&#x6001;&#xFF0C;&#x8981;&#x4E48;&#x53EA;&#x80FD;&#x5728; render &#x9636;&#x6BB5;&#xFF0C;&#x4E0D;&#x80FD;&#x5904;&#x4E8E; commit &#x9636;&#x6BB5;&#xFF08;&#x6BD4;&#x8F83;&#x597D;&#x5947;&#x4EC0;&#x4E48;&#x65F6;&#x5019;&#x4F1A;&#x5728; commit &#x9636;&#x6BB5;&#x6709;&#x65B0;&#x7684;&#x4EFB;&#x52A1;&#x8FDB;&#x6765;&#xFF0C;commit &#x90FD;&#x662F;&#x540C;&#x6B65;&#x7684;&#x65E0;&#x6CD5;&#x6253;&#x65AD;&#xFF09;&#x3002;&#x8FD8;&#x6709;&#x4E00;&#x4E2A;&#x9009;&#x9879;<code>nextRoot !== root</code>&#xFF0C;&#x8FD9;&#x4E2A;&#x7684;&#x610F;&#x601D;&#x5C31;&#x662F;&#x4F60;&#x7684; APP &#x5982;&#x679C;&#x6709;&#x4E24;&#x4E2A;&#x4E0D;&#x540C;&#x7684; root&#xFF0C;&#x8FD9;&#x65F6;&#x5019;&#x4E5F;&#x7B26;&#x5408;&#x6761;&#x4EF6;&#x3002;</p><p>&#x5728;&#x7B26;&#x5408;&#x6761;&#x4EF6;&#x4E4B;&#x540E;&#x5C31;<code>requestWork</code>&#x4E86;</p></div><div class="api-method-code"><div class="api-method-sample" data-lang="js" data-name="JavaScript"><pre><code class="lang-js"><span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">scheduleWork</span>(<span class="hljs-params">fiber: Fiber, expirationTime: ExpirationTime</span>) </span>{
  <span class="hljs-keyword">const</span> root = scheduleWorkToRoot(fiber, expirationTime)

  <span class="hljs-keyword">if</span> (enableSchedulerTracing) {
    storeInteractionsForExpirationTime(root, expirationTime, <span class="hljs-literal">true</span>)
  }

  <span class="hljs-keyword">if</span> (
    !isWorking &amp;&amp;
    nextRenderExpirationTime !== NoWork &amp;&amp;
    expirationTime &lt; nextRenderExpirationTime
  ) {
    <span class="hljs-comment">// This is an interruption. (Used for performance tracking.)</span>
    interruptedBy = fiber
    resetStack()
  }
  markPendingPriorityLevel(root, expirationTime)
  <span class="hljs-keyword">if</span> (
    <span class="hljs-comment">// If we&apos;re in the render phase, we don&apos;t need to schedule this root</span>
    <span class="hljs-comment">// for an update, because we&apos;ll do it before we exit...</span>
    !isWorking ||
    isCommitting ||
    <span class="hljs-comment">// ...unless this is a different root than the one we&apos;re rendering.</span>
    nextRoot !== root
  ) {
    <span class="hljs-keyword">const</span> rootExpirationTime = root.expirationTime
    requestWork(root, rootExpirationTime)
  }
}

<span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">scheduleWorkToRoot</span>(<span class="hljs-params">fiber: Fiber, expirationTime</span>): <span class="hljs-title">FiberRoot</span> | <span class="hljs-title">null</span> </span>{
  <span class="hljs-comment">// Update the source fiber&apos;s expiration time</span>
  <span class="hljs-keyword">if</span> (
    fiber.expirationTime === NoWork ||
    fiber.expirationTime &gt; expirationTime
  ) {
    fiber.expirationTime = expirationTime
  }
  <span class="hljs-keyword">let</span> alternate = fiber.alternate
  <span class="hljs-keyword">if</span> (
    alternate !== <span class="hljs-literal">null</span> &amp;&amp;
    (alternate.expirationTime === NoWork ||
      alternate.expirationTime &gt; expirationTime)
  ) {
    alternate.expirationTime = expirationTime
  }
  <span class="hljs-comment">// Walk the parent path to the root and update the child expiration time.</span>
  <span class="hljs-keyword">let</span> node = fiber.return
  <span class="hljs-keyword">if</span> (node === <span class="hljs-literal">null</span> &amp;&amp; fiber.tag === HostRoot) {
    <span class="hljs-keyword">return</span> fiber.stateNode
  }
  <span class="hljs-keyword">while</span> (node !== <span class="hljs-literal">null</span>) {
    alternate = node.alternate
    <span class="hljs-keyword">if</span> (
      node.childExpirationTime === NoWork ||
      node.childExpirationTime &gt; expirationTime
    ) {
      node.childExpirationTime = expirationTime
      <span class="hljs-keyword">if</span> (
        alternate !== <span class="hljs-literal">null</span> &amp;&amp;
        (alternate.childExpirationTime === NoWork ||
          alternate.childExpirationTime &gt; expirationTime)
      ) {
        alternate.childExpirationTime = expirationTime
      }
    } <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> (
      alternate !== <span class="hljs-literal">null</span> &amp;&amp;
      (alternate.childExpirationTime === NoWork ||
        alternate.childExpirationTime &gt; expirationTime)
    ) {
      alternate.childExpirationTime = expirationTime
    }
    <span class="hljs-keyword">if</span> (node.return === <span class="hljs-literal">null</span> &amp;&amp; node.tag === HostRoot) {
      <span class="hljs-keyword">return</span> node.stateNode
    }
    node = node.return
  }
  <span class="hljs-keyword">return</span> <span class="hljs-literal">null</span>
}

<span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">resetStack</span>(<span class="hljs-params"></span>) </span>{
  <span class="hljs-keyword">if</span> (nextUnitOfWork !== <span class="hljs-literal">null</span>) {
    <span class="hljs-keyword">let</span> interruptedWork = nextUnitOfWork.return
    <span class="hljs-keyword">while</span> (interruptedWork !== <span class="hljs-literal">null</span>) {
      unwindInterruptedWork(interruptedWork)
      interruptedWork = interruptedWork.return
    }
  }

  nextRoot = <span class="hljs-literal">null</span>
  nextRenderExpirationTime = NoWork
  nextLatestAbsoluteTimeoutMs = <span class="hljs-number">-1</span>
  nextRenderDidError = <span class="hljs-literal">false</span>
  nextUnitOfWork = <span class="hljs-literal">null</span>
}</code></pre>
</div></div></div>



<div class="api-method"><div class="api-method-definition"><h1 id="requestwork">requestWork</h1><p><code>addRootToSchedule</code>&#x628A; root &#x52A0;&#x5165;&#x5230;&#x8C03;&#x5EA6;&#x961F;&#x5217;&#xFF0C;&#x4F46;&#x662F;&#x8981;&#x6CE8;&#x610F;&#x4E00;&#x70B9;&#xFF0C;&#x4E0D;&#x4F1A;&#x5B58;&#x5728;&#x4E24;&#x4E2A;&#x76F8;&#x540C;&#x7684; root &#x524D;&#x540E;&#x51FA;&#x73B0;&#x5728;&#x961F;&#x5217;&#x4E2D;</p><p>&#x53EF;&#x4EE5;&#x770B;&#x51FA;&#x6765;&#xFF0C;&#x5982;&#x679C;&#x7B2C;&#x4E00;&#x6B21;&#x8C03;&#x7528;<code>addRootToSchedule</code>&#x7684;&#x65F6;&#x5019;&#xFF0C;<code>nextScheduledRoot</code>&#x662F;<code>null</code>&#xFF0C;&#x8FD9;&#x65F6;&#x5019;&#x516C;&#x5171;&#x53D8;&#x91CF;<code>firstScheduledRoot</code>&#x548C;<code>lastScheduledRoot</code>&#x4E5F;&#x662F;<code>null</code>&#xFF0C;&#x6240;&#x4EE5;&#x4F1A;&#x628A;&#x4ED6;&#x4EEC;&#x90FD;&#x8D4B;&#x503C;&#x6210;<code>root</code>&#xFF0C;&#x540C;&#x65F6;<code>root.nextScheduledRoot = root</code>&#x3002;&#x7136;&#x540E;&#x7B2C;&#x4E8C;&#x6B21;&#x8FDB;&#x6765;&#x7684;&#x65F6;&#x5019;&#xFF0C;&#x5982;&#x679C;&#x524D;&#x540E;<code>root</code>&#x662F;&#x540C;&#x4E00;&#x4E2A;&#xFF0C;&#x90A3;&#x4E48;&#x4E4B;&#x524D;&#x7684;<code>firstScheduledRoot</code>&#x548C;<code>lastScheduledRoot</code>&#x90FD;&#x662F; root&#xFF0C;&#x6240;&#x4EE5;<code>lastScheduledRoot.nextScheduledRoot = root</code>&#x5C31;&#x7B49;&#x4E8E;<code>root.nextScheduledRoot = root</code></p><p>&#x8FD9;&#x4E48;&#x505A;&#x662F;&#x56E0;&#x4E3A;&#x540C;&#x4E00;&#x4E2A;<code>root</code>&#x4E0D;&#x9700;&#x8981;&#x5B58;&#x5728;&#x4E24;&#x4E2A;&#xFF0C;&#x56E0;&#x4E3A;&#x524D;&#x4E00;&#x6B21;&#x8C03;&#x5EA6;&#x5982;&#x679C;&#x4E2D;&#x9014;&#x88AB;&#x6253;&#x65AD;&#xFF0C;&#x4E0B;&#x4E00;&#x6B21;&#x8C03;&#x5EA6;&#x8FDB;&#x5165;&#x8FD8;&#x662F;&#x4ECE;&#x540C;&#x4E00;&#x4E2A;<code>root</code>&#x5F00;&#x59CB;&#xFF0C;&#x5C31;&#x4F1A;&#x628A;&#x65B0;&#x7684;&#x4EFB;&#x52A1;&#x4E00;&#x8D77;&#x6267;&#x884C;&#x4E86;&#x3002;</p><p>&#x4E4B;&#x540E;&#x6839;&#x636E;<code>expirationTime</code>&#x8C03;&#x7528;<code>performSyncWork</code>&#x8FD8;&#x662F;<code>scheduleCallbackWithExpirationTime</code></p><p><code>scheduleCallbackWithExpirationTime</code>&#x662F;&#x6839;&#x636E;&#x65F6;&#x95F4;&#x7247;&#x6765;&#x6267;&#x884C;&#x4EFB;&#x52A1;&#x7684;&#xFF0C;&#x4F1A;&#x6D89;&#x53CA;&#x5230;<code>requestIdleCallback</code>&#xFF0C;&#x8BE6;&#x7EC6;&#x89E3;&#x6790;&#x770B;<a href="react-scheduler.md">&#x8FD9;&#x91CC;</a></p><p><code>isBatchingUpdates</code>&#x548C;<code>isUnbatchingUpdates</code>&#x6D89;&#x53CA;&#x5230;&#x4E8B;&#x4EF6;&#x7CFB;&#x7EDF;&#xFF0C;&#x770B;<a href="../event-system/README.md">React &#x4E8B;&#x4EF6;&#x7CFB;&#x7EDF;</a></p><p>&#x4ED6;&#x4EEC;&#x6700;&#x7EC8;&#x90FD;&#x8981;&#x8C03;&#x7528;<code>performWork</code></p></div><div class="api-method-code"><div class="api-method-sample" data-lang="js" data-name="JavaScript"><pre><code class="lang-js"><span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">requestWork</span>(<span class="hljs-params">root: FiberRoot, expirationTime: ExpirationTime</span>) </span>{
  addRootToSchedule(root, expirationTime)
  <span class="hljs-keyword">if</span> (isRendering) {
    <span class="hljs-comment">// Prevent reentrancy. Remaining work will be scheduled at the end of</span>
    <span class="hljs-comment">// the currently rendering batch.</span>
    <span class="hljs-keyword">return</span>
  }

  <span class="hljs-keyword">if</span> (isBatchingUpdates) {
    <span class="hljs-comment">// Flush work at the end of the batch.</span>
    <span class="hljs-keyword">if</span> (isUnbatchingUpdates) {
      nextFlushedRoot = root
      nextFlushedExpirationTime = Sync
      performWorkOnRoot(root, Sync, <span class="hljs-literal">true</span>)
    }
    <span class="hljs-keyword">return</span>
  }

  <span class="hljs-keyword">if</span> (expirationTime === Sync) {
    performSyncWork()
  } <span class="hljs-keyword">else</span> {
    scheduleCallbackWithExpirationTime(root, expirationTime)
  }
}

<span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">addRootToSchedule</span>(<span class="hljs-params">root: FiberRoot, expirationTime: ExpirationTime</span>) </span>{
  <span class="hljs-comment">// Add the root to the schedule.</span>
  <span class="hljs-comment">// Check if this root is already part of the schedule.</span>
  <span class="hljs-keyword">if</span> (root.nextScheduledRoot === <span class="hljs-literal">null</span>) {
    <span class="hljs-comment">// This root is not already scheduled. Add it.</span>
    root.expirationTime = expirationTime
    <span class="hljs-keyword">if</span> (lastScheduledRoot === <span class="hljs-literal">null</span>) {
      firstScheduledRoot = lastScheduledRoot = root
      root.nextScheduledRoot = root
    } <span class="hljs-keyword">else</span> {
      lastScheduledRoot.nextScheduledRoot = root
      lastScheduledRoot = root
      lastScheduledRoot.nextScheduledRoot = firstScheduledRoot
    }
  } <span class="hljs-keyword">else</span> {
    <span class="hljs-comment">// This root is already scheduled, but its priority may have increased.</span>
    <span class="hljs-keyword">const</span> remainingExpirationTime = root.expirationTime
    <span class="hljs-keyword">if</span> (
      remainingExpirationTime === NoWork ||
      expirationTime &lt; remainingExpirationTime
    ) {
      <span class="hljs-comment">// Update the priority.</span>
      root.expirationTime = expirationTime
    }
  }
}</code></pre>
</div></div></div>



<p>&#x5173;&#x4E8E;<code>scheduleCallbackWithExpirationTime</code>&#x7684;&#x770B;<a href="scheduler-pkg.html">&#x8FD9;&#x91CC;</a></p><p>&#x63A5;&#x4E0B;&#x53BB;&#x5C31;&#x8FDB;&#x5165;&#x4E86;<a href="perform-work.html"><code>performWork</code>&#x9636;&#x6BB5;</a></p>
                                
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